Method of producing slivers from synthetic fiber tows



April 16, 1968 TAKEJI ARA| ET AL 3,377,663

METHOD OF PRODUCING SLIVERS FROM SYNTHETIC FIBER TOWS Filed Oct. 15, 1965 wd/4;, %W TNVENTQRS swam United States Patent 3,377,663 METHOD OF PRODUCING SLIVERS FROM SYNTHETIC FIBER TOWS Takeji Arai, Toyonaka-shi, Osaka-fa, and Masahiko Ariga and Sukehiro Yoshiyama, Amagasaki-shi, Japan, assignors to O-M Ltd., Osaka-shi, Japan Filed Oct. 13, 1965, Ser. No. 495,561 3 Claims. (Cl. 19--.39)

ABSTRACT OF THE DISCLOSURE An apparatus for producing slivers by tension breaking synthetic fiber tow in a single operation, comprising three stations in operative sequence, the first station comprising rough tension breaking means for tension breaking the filaments of the tow into long lengths compared to the final lengths of the filaments, said means being two pairs of nip rollers and a pair of opposed conveyor means between the two pairs of nip rollers, the second station comprising moderate tension breaking means for tension breaking the long length of tension broken filaments into lengths of from about 4 to about 6 inches, said means being two pairs of nip rollers, the third station comprising short tension breaking means for tension breaking the 4-6 inch tension broken filaments into lengths of about 1% to 2 /2 inches, said means being two pairs of nip rollers, at least two vertically positioned blade means between said two pairs of nip rollers, and means coupled to at least one of said blade means for vertically reciprocating said at least one blade means.

This invention relates to a method of producing slivers from synthetic fiber tows by tension breaking the latter in one operation.

A known converter has heretofore been used in cutting or tension breaking synthetic fiber tows into desired lengths of 3 /z7". However, the cutting or tension breaking of synthetic fiber tows by the known converter, though providing some satisfaction with respect to the cutting size, requires use of a complicated additional mechanism for the treatment of the fibers after they are cut, with the use of which additional mechanism it is impossible to produce a satisfactory spinnable sliver. Generally, fibers having a staple length of less than 3" or those for use in mixed fiber spinning with cotton having a staple length of less than 1%" cannot be produced by the known converter. Further, the use of the known concerter causes drawbacks such as irregularities in fiber separation, density distribution at fiber tips and parallelism, and fusion at the cut ends, and occurrence of neps and fishfood (fiber material in powder form produced at the cut ends), the adverse effect of said drawbacks actually carrying all the way to the final products, thereby hindering the achievement of satisfactory results. Also, since the conventional converter system is complicated, the above-mentioned troubles occur often and make high speed operation impossible.

The present invention provides a novel and improved method which eliminates the aforesaid troubles, makes possible the production in one operation of a sliver of fibers having a staple length of the order of 1% for use in mixed fiber spinning with cotton or a sliver of fibers having a staple length of less than 3", which has heretofore been considered impossible, and makes possible the production of slivers which are superior in in quality to those produced through the conventiona1 drawing process.

Another advantage of the invention is that simplification of the mechanism is possible which, in turn, allows high speed operation of the machine. Thus, there can be obtained an efficient and economic apparatus which provides an increased output several times higher than before.

The invention will now be described in more detail with reference to the accompanying drawing showing an embodiment of the invention.

In the drawings:

FIG. 1 is a side view illustrating a roller arrangement wherein three steps, i.e., rough tension breaking, medium tension breaking and short tension breaking are combined;

FIG. 2 is an enlarged side view of the short tension breaking station; and

FIG. 3 is a front view of said station.

Tow 2 contained in containers 1 are drawn therefrom by a first back nip roller assembly 6 while they are controlled with respect to their thickness and width by eans of spread bars 3, 4 and 5. Located between said first back nip roller assembly and spread bars are a number of resistance bars 7 arranged in a zigzag pattern, so that a uniform tension is imparted to each tow. The tows issuing from the first back nip roller assembly are stretched 1.21.5 times in a preliminary stretch zone (A) formed at the rear of a heat stretch zone (B). The preliminary stretch zone is constituted by the first and second back nip roller assemblies 6 and '8. The heat stretch zone is located between the second and third back nip roller assemblies 8 and 9 and includes a pair of radiant heat plates 10 located above and below the tow path. The tows which have been spread are passed between the radian heat plates, thereby thermally stretching the same. The stretch ratio at the heat stretch zone is so as to be 1.2-1.6, the heating temperature being l20-160 C. Thus, the heat stretch zone is so constructed that it may be adjusted to provide an appropriate stretch ratio and temperature within said limits in accordance with the kinds of the tows to be processed. After passing through the heat stretch zone and just before being nipped by the third back nip roller assembly, the tows are aircooled by a suitable air cooling means and fed to a rough tension breaking station (C), which is constituted by the third and fourth back nip roller assemblies 9 and 11. The stretch ratio at said station is so selected as to provide a tension which is several times as high as the force required for tension breaking the tows. The nipping or gripping force of said back nip roller assembly is selected to be enough to endure the tension breaking force in said stretch ratio. The roller gauge between the two back nip roller assemblies is about 30 inches. The points where the tension breaking occurs in this rough tension breaking station are in the Weakest places of the tows, most of the cut areas occurring at points in the front half of the distance between the two roller assemblies. It is seen that upon the cutting of a tow, the sretching effect disappears to cause the tow to quickly shrink thereby to form hooks theeron. In order to prevent the occurrence of such hooks, the present invention provides a pair of upper and lower conveyors located between the third and fourth back nip roller assemblies for lightly holding tows therebetween, said conveyors extending from the middle of the distance between the two back nip roller assemblies toward the front. As a result of this arrangement, the tows which have been cut are drawn out at a high speed by the fourth nip roller assembly, with the rear end hooks effectively eliminated, and even if such hooks occur at front cut ends the fibers can be parallelly straightened by the action of the fractional resistance exerted by the high speed running tows and in this manner the tows are nipped by the fourth nip roller assembly without the danger of the tows be coming entwined with each other. The tows thus tension broken at the rough tension breaking station will then be forwarded to a medium tension breaking station (D). This station is constituted by the fourth and fifth nip roller assemblies 11 and 13, wherein the tows nipped between the two assemblies are cut into lengths of the order of 4"-6". Thus, the medium tension breaking station is so constructed that its roller gauge may be set to provide a resulting cut staple length which is %%i times as long as the staple length at the preceding station (C). The tows thus cut at this medium tension breaking station are then controlled by calender rollers 14 to ge given a required ribbon form of suitable width and thickness which is then forwarded to the next process. If it is desired to produce a long fiber whose required staple length is above 4", the above-mentioned processes sufiice for this purpose, and thus the sliver drawn from the calender rollers may be immediately collected in a can.

Roller tension breaking processes for tension breaking tows is known. One of the features of the present inven tion is that by utilizing the known roller tension breaking process, a number of said mechanisms are parallelly arranged to produce ribbon-like slivers having a predetermined staple length and the thus produced slivers are overlapped one upon another and forwarded to the succeeding processes, during which tension breaking and elimination of hooks are repeatedly efiected, and that the apparatus is adapted to provide satisfactory stretch ratios for producing the desired slivers.

A further description will now be given of an instance in which it is desired to obtain a short cut sliver having a staple length of the order of PAW-2V2".

A number of ribbons obtained by the aforesaid arrangement are overlapped one upon another and forwarded to a preliminary tension breaking station (E) which precedes a short tension breaking station (F). The preliminary tension breaking station (E) is constituted by a back roller assembly 16 and a third roller assembly 17 and is so constructed that its roller gauge can be set at a value somewhat greater than the required staple length and the two roller assemblies can sufficiently nip the fibers to apply an appropriate stretch ratio thereto, thereby effecting the intended preliminary tension breaking. The filaments treated at the preliminary tension breaking station are then forwarded to the succeeding short tension breaking station. In the latter station, as shown in FIG. 2, the second and third roller assemblies 17 and 18 are positioned close to each other which allows them to firmly nip the fibers and there are also provided a pair of upper and lower blades 19 positioned midway of the two roller assemblies and above and below the filament line. The upper blade has at its front end a rounded surface and is so secured to a bracket 20 that the front end will be close to the filament line, while the lower blade has at its front end an oblique rounded surface and is held in a guide 21 so as to be vertically vibrated therein by means of a lever 22.

As a vibrator mechnaism for said lever, a spring 23 urges one end of said lever against a cam 24, the rotation of said cam causing the lower blade to be vertically reciprocated thereby to strike the tensioned portions of the filaments to break the latter. The cycle of the vertical movements of this blade is determined by the speed at which the filaments are tension broken. Besides this method of providing such movements by a cam, a magnetically operating method may be used for this purpose. The filaments broken at the short tension breaking station in this way are passed through the second roller to be nipped by a front roller assembly 25, so that miscutting is prevented and also the correction of the degree of fiber separation is effected, whereby there is obtained a ribbon of the required staple length with a perfect parallelism and fiber separation which is passed through a condenser 26 and calendar rollers 27 to a crimper box 28, wherefrom it is collected in a can 29 as a good quality sliver by means of a coiler motion (not shown).

In short, the aforesaid short tension breaking station has been developed to overcome the problems of the roller strength, caused by the inevitability of reducing roller gauges, and the extreme bias cut inherent in the conventional tension breaking method, thereby preventing the inclusion of a large amount of short fibers and making possible the obtaining of satisfactory fibers resembling natural fibers in their staple diagram.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in details of construction and arrangement may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. An apparatus for producing slivers by tension breaking synthetic fiber tow in a single operation, comprising three stations in operative sequnece, the first station comprising rough tension breaking means for tension breaking the filaments of the tow into long lengths compared to the final lengths of the filaments, said means being two pairs of nip rollers and a pair of opposed conveyor means between the two pairs of nip rollers, the sec ond station comprising moderate tension breaking means for tension breaking the long lengths of tension broken filaments into lengths of from about 4 to about 6 inches, said means being two pairs of nip rollers, the third station comprising short tension breaking means for tension breaking the 4-6 inch tension broken filaments into lengths of about 1% to 2 /2 inches, said means being two pairs of nip rollers, at least two vertically positioned blade means between said two pairs of nip rollers, and means coupled to at least one of said blade means for vertically reciprocating said at least one blade means.

2. An apparatus as claimed in claim 1 in which said conveyor means is disposed between the pair of nip rollers toward which the tow is running and the midpoint between the pairs of nip rollers comprising said first station, and said conveyor means each being an endless conveyor, said conveyors spaced from each other so as to apply a light pressure to the tow passing between them and including driving means for driving the conveyors at a speed somewhat greater than the surface speed of the nip rollers toward which the conveyors are running.

3. An apparatus as claimed in claim 1 in which said blade means comprises a pair of blades which are offset slightly in the direction of the length of the tow and having the edges thereof spaced from each other in the vertical direction so that when one of the blades is reciprocated it strikes the tow and causes the tow to strike the other blade.

References Cited UNITED STATES PATENTS 2,081,997 6/1937 Hale et al. 19--.41 2,641,804 6/1953 Klein 19--.35 1,154,870 9/1915 Maly 19242 2,082,840 6/1937 Lohrke 19.39 2,679,070 5/1954 Hood 19.37 2,976,578 3/1961 Virgil 19-.37

FOREIGN PATENTS 716,043 9/ 1954 Great Britain. 865,575 2/ 1953 Germany.

MERVIN STEIN, Primary Examiner.

I. C. WADDEY, Assistant Examiner. 

